niet

Get data from yaml file directly in your shell

Install or Update niet

$ pip install -U niet

Requirements

• Python 2.7+

Usage

With YAML file

Consider the yaml file with the following content:

# /path/to/your/file.yaml
project:
    meta:
        name: my-project
    foo: bar
    list-items:
        - item1
        - item2
        - item3

You can retrieve data from this file by using niet like this:

$ niet /path/to/your/file.yaml ".project.meta.name"
my-project
$ niet /path/to/your/file.yaml ".project.foo"
bar
$ niet /path/to/your/file.yaml ".project.list-items"
item1 item2 item3
$ # assign return value to shell variable
$ NAME=$(niet /path/to/your/file.yaml ".project.meta.name")
$ echo $NAME
my-project

With JSON file

Consider the json file with the following content:

{
    "project": {
        "meta": {
            "name": "my-project"
        }
    },
    "foo": "bar",
    "list-items": [
        "item1",
        "item2",
        "item3"
    ]
}

You can retrieve data from this file by using niet like this:

$ niet /path/to/your/file.json "project.meta.name"
my-project
$ niet /path/to/your/file.json "project.foo"
bar
$ niet /path/to/your/file.json "project.list-items"
item1 item2 item3
$ # assign return value to shell variable
$ NAME=$(niet /path/to/your/file.json "project.meta.name")
$ echo $NAME
my-project

Output formats

You can change the output format using the -f or --format optional argument.

By default, niet detect the input format and display complex objects in the same format. If the object is a list or a value, newline output format will be used.

Output formats are:

• ifs
• squote
• dquote
• newline
• yaml
• json

ifs

Ifs output format print all values of a list or a single value in one line. All values are separated by the content of IFS environment variable if defined, space otherwise. This is usefull in a shell for loop, but your content must, of course, don't contain IFS value.

OIFS="$IFS"
IFS="|"
for i in $(niet tests/samples/sample.yaml .project.list-items -f ifs); do
	echo $i
done
IFS="$OIFS"

squote

Squotes output format print all values of a list or a single value in one line. All values are quoted with single quotes and are separated by IFS value.

dquote

Dquotes output format print all values of a list or a single value in one line. All values are quoted with a double quotes and are separated by IFS value.

newline

Newline output format print one value of a list or a single value per line. This format is usefull using shell while read loop. eg:

while read value: do
	echo $value
done < $(niet --format newline your-file.json project.list-items)

yaml

Yaml output format force output to be in YAML regardless the input file format.

json

Json output format force output to be in JSON regardless the input file format.

Deal with errors

When your JSON file content are not valid niet display an error and exit with return code 1

You can easily protect your script like this:

PROJECT_NAME=$(niet your-file.yaml project.meta.name)
if [ "$?" = "1" ]; then
    echo "Error occur ${PROJECT_NAME}"
else
    echo "Project name: ${PROJECT_NAME}"
fi

Examples

You can try niet by using the samples provided with the project sources code.

Sample example:

# tests/samples/sample.yaml
project:
    meta:
        name: project-sample
        tags:
          - example
          - sample
          - for
          - testing
          - purpose

Retrieve the project name:

$ niet tests/samples/sample.yaml project.meta.name
project-sample

Deal with list of items

$ for el in $(niet tests/samples/sample.yaml project.meta.tags); do echo ${el}; done
example
sample
for
testing
purpose

Tips

You can pass your search with or without quotes like this:

$ niet your-file.yaml project.meta.name
$ niet your-file.yaml "project.meta.name"

Contribute

If you want to contribute to niet please first read the contribution guidelines

Licence

This project is under the MIT License.

See the license file for more details

Hervé Beraud herveberaud.pro@gmail.com